Buick V6 conversion

[4bait]

Re: Buick V6 conversion

Since the shipment turned up I have a whole swag of new bits to play with and make fit.

Here is the Mercruiser drive plate machined down centred up and redrilled to suit the Holden Flywheel,

Next was to get the Mercruiser chevy bell housing to fit, Tried it on and the 2 top holes came close to lining up so I elongated them a bit and got it to bolt on in the correct position, Then started drilling out the remaining holes and was preparing to weld on some lugs for the mounting position, then thought it was too big and stuck out in all the wrong places, it would have done the job but it looked crap. I want the conversion to look like it's mean't to be there and not just bits and peices tacked in here and there. so I scrapped the idea and went to plan B.

This is the Chev Bell housing on the block for any one interested to see how different they are. Also the starter motor cutout was on the wrong side. The white line shows where I was going to cut it off before changing my mind.
it's not crooked I just took the pic on a funny angle sorry

Plan B was to cut the front of an old VN Commodore T700 auto transmission. (lucky me I had one sitting around spare after I put the same Motor in to my Hilux)

Here is the cut off section bolted to the block

Then I cut the middle out of the Chevy bell housing and spent about 3 hours lining them up in the correct position (hopefully) before welding the two together to make one.

And heres a pic of it fitted to the engine block

Hopefully it is all welded together in the correct position, but I will find out for sure on Wednesday when I bolt the transom assy to the boat and sit the motor in so fingers crossed.

I did bolt the transom plate to the bellhousing and put the alignment bar in and the bar came through the centre of the hole, but this can change depending on the angle of the transom and whether or not I had the plate sitting on the exact same angle, ( hopefully my angle Gauge doesn?t lie LOL)


Cheers Andy

 

[achris]

Re: Buick V6 conversion

That new flywheel housing is seriously impressive... Well done.

Did you take any drawings or molds? You might have found yourself a very lucrative market. I'm sure there are a lot of people in Australia who would do a Commodore V6 conversion if the bits were available. There are a lot of 470 and old 165 owners out there who are not re-powering because of the cost. If you offered a kit to re-power with a $1500(ish) V6 they'd jump at it...(Need a WA agent?)

Chris.....

 

[betayv]

Re: Buick V6 conversion

UAUAUAooo great job very impresive keep the good work.

 

[4bait]

Re: Buick V6 conversion

That new flywheel housing is seriously impressive... Well done.

Did you take any drawings or molds? You might have found yourself a very lucrative market. I'm sure there are a lot of people in Australia who would do a Commodore V6 conversion if the bits were available. There are a lot of 470 and old 165 owners out there who are not re-powering because of the cost. If you offered a kit to re-power with a $1500(ish) V6 they'd jump at it...(Need a WA agent?)

Chris.....

nope no drawings just measured and made, but it would be easy to reproduce if need be once I know everything lines up properly. If it works then it may be worth while doing a mould and casting some who knows

This one is simply just the front cut off a commodore v6 turbo 700 transmision at the correct thickness and the middle of the chev housing welded in, then relocated the starter position to the opposite side, and shaped it a bit, so basically you would need to purchase an old one of each to make one unit.

I bought the old trany complete and going of Ebay some time ago for $10 because I needed parts for the ute.

In General I don't think this is really a hard conversion the manifolds can be purchased already from a few different people, the bellhousing was the only issue for the Gen 11. ( I may eat my words if it doesn't work LOL)

Wasp in NZ do a bellhousing for the early model legs just not the later ones. and they also do engine mount kits and the computor and wiring harness and Cast alloy manifolds etc if you want them but then the $$$ really start to add up, everything else is just mucking around.

I think the only reason this looks so involved is because i'm doing the lot myself from scratch, I love doing this sort of thing and as many on here would know with their own projects the satisfaction is great when you get to enjoy the end result.

and the real big advantage is if this motor blows up then I know I can get anther for around $50 that will bolt straight in LOL

cheers Andy

 

[achris]

Re: Buick V6 conversion

...and the real big advantage is if this motor blows up then I know I can get anther for around $50 that will bolt straight in LOL

cheers Andy

My point precisely.... (every time my 4.3 breaks it's big bucks to get parts. )

Just a few questions... What's the maximum power output of the 3.8? And what ratio leg do you have? What prop will you be running?

I do have some suggestions in this area... SS prop, without a doubt, probably a Vengance or better, an Offshore (4 blade). Don't go for too big diameter (like a Mirage), they have too much bow lift for these deep Vee hulls, 14 inch max. Leg ratio should be a 1.81 and the prop will probably end up being around the 21" or 23" mark.

Just my thoughts...

Cheers,

Chris..........

 

[jtybt]

Re: Buick V6 conversion

I think that exhaust came out great. Only thing I can suggest is to extend the water jacket and point where the raw water mixes with the exhaust.

like this

The water mixes where the buggered up welds are because I had to cut and close off more and more where the water mixed with the exhaust.

You may see the need in the future when you see rust in the exhaust ports.

 

[4bait]

Re: Buick V6 conversion

My point precisely.... (every time my 4.3 breaks it's big bucks to get parts. )

Just a few questions... What's the maximum power output of the 3.8? And what ratio leg do you have? What prop will you be running?

I do have some suggestions in this area... SS prop, without a doubt, probably a Vengance or better, an Offshore (4 blade). Don't go for too big diameter (like a Mirage), they have too much bow lift for these deep Vee hulls, 14 inch max. Leg ratio should be a 1.81 and the prop will probably end up being around the 21" or 23" mark.

Just my thoughts...

Cheers,

Chris..........

Hey Chris

The new leg was sold as a V6 ratio but haven't checked it yet. the old 470 one is stamped 1.84r

The old 470 was 170 h/p and the Holden V6 as standard is also 170h/p but the torque should be much better especially low down grunt, can get 200 h/p with a few computer chip mods and can get 350 plus with some engine bolt ons but 200 hp is what I would like to aim for maybe 250 max.

Since both motors are similar H/P and both drives are similar ratio's I was planning starting with a 19p prop and see how it goes. The old Prop was an alloy 4 blade 14-1/4 inch Solas with a 17 pitch and it pushed the boat at just under 30 knots at 4200rpm WOT

I have a 11 pitch 15 pitch 17 pitch 19 pitch 21 pitch and a 23 pitch here so there are a few to choose from once I have a starting point to try.
I am guessing 19p to 21p will end up being about right for this boat but time will tell, if it does handle something like the 21p then that would be nice. The boat weighs around 2 tonne I think so there is a bit to push.

Personally I don't want a stainless prop as the last time I had one on and hit a submerged object it destroyed both my gearbox and the prop which cost me big $$$, If it had an alloy prop on at the time the gear box probably would have survived with only prop damage.

Unfortunately I often travel down a creek under a bridge when launching and mongrels chuck shopping trolleys and stuff of the bridge and that?s what I hit last time. Also When in Western Port Bay it is very tidal and have unfortunately found my self in shallow water doing some dredging LOL on a couple of Occasions, so for my purpose I think Alloy is the better option for now.

cheers Andy

 

[4bait]

Re: Buick V6 conversion

I think that exhaust came out great. Only thing I can suggest is to extend the water jacket and point where the raw water mixes with the exhaust.

like this

[The water mixes where the buggered up welds are because I had to cut and close off more and more where the water mixed with the exhaust.

You may see the need in the future when you see rust in the exhaust ports.

Yep I could end up changing them yet as at this stage it will be all trial and error and there will no doubt be some teething problems along the way, Hopefully only minor ones.

The ones I built are set up simalar to some shop bought ones that sell here for $2500 and they put a 5 year warruntee on them so I figured why not make them like that if they work and see how it goes from there.


Have you got anoids in yours? and do they make a difference with the rust in the stainless? I have put some in mine.


Cheers Andy

 

[Howard Sterndrive]

Re: Buick V6 conversion

Is that a tube with the trim hoses running through it?

 

[achris]

Re: Buick V6 conversion

Is that a tube with the trim hoses running through it?

Nope... That's what we call a 'burley bucket'. You throw fish and other stuff you want to use as burley in there. The bucket has holes in it so as you crush up the burley it leaks slowly out the bucket and (hopefully) attracts fish....

Chris.......

The trim hoses can be seen in the usual place going into the manifold under the gimbal housing if you look closely.

 

[achris]

Re: Buick V6 conversion

Hey Chris

The new leg was sold as a V6 ratio but haven't checked it yet. the old 470 one is stamped 1.84r

V6 come out with 2 different ratio, depending on the era. Earlier ones were 1.81, later were 1.62.

The old 470 was 170 h/p and the Holden V6 as standard is also 170h/p but the torque should be much better especially low down grunt, can get 200 h/p with a few computer chip mods and can get 350 plus with some engine bolt ons but 200 hp is what I would like to aim for maybe 250 max.

200 as the target is perfect. Too much power and you end up with a bigger (pitch) prop, and when you're cruising the engine speed is too low, off the back of the power curve, and it can be a struggle to maintain a constant low speed, especially in a bit of a swell.

Since both motors are similar H/P and both drives are similar ratio's I was planning starting with a 19p prop and see how it goes. The old Prop was an alloy 4 blade 14-1/4 inch Solas with a 17 pitch and it pushed the boat at just under 30 knots at 4200rpm WOT

I have a 11 pitch 15 pitch 17 pitch 19 pitch 21 pitch and a 23 pitch here so there are a few to choose from once I have a starting point to try.
I am guessing 19p to 21p will end up being about right for this boat but time will tell, if it does handle something like the 21p then that would be nice. The boat weighs around 2 tonne I think so there is a bit to push.

My old V6 (205hp at the crankshaft) had a 1.84:1 leg and I was turning a 21" prop and still pulling too many revs, so a 21 is not out of the question. I ended up staying with that prop anyway because it was so much better at cruising speeds, and the days you got to go full noise are so rare it wasn't worth changing. I like running 1 prop smaller, it is much easier on engines and drives, makes the boat so much easier to drive, and (believe it or not) uses slightly LESS fuel, even though the engine's spinning a little quicker.

Personally I don't want a stainless prop as the last time I had one on and hit a submerged object it destroyed both my gearbox and the prop which cost me big $$$, If it had an alloy prop on at the time the gear box probably would have survived with only prop damage.

Yeah, I've heard this argument a thousand times... 'Ali props save the leg'... Not true, sorry. When I had my boatshop I saw SS props folded up like paper. I expected to see a grenaded gearset... When I stripped the box, some were, some weren't. I've also seen gearboxes with the insides like a war zone, wearing an ali prop with a little bit of a scratch on the blades... I think the damage done in more down to the lap of the gods than to the material the prop is made of.

Unfortunately I often travel down a creek under a bridge when launching and mongrels chuck shopping trolleys and stuff of the bridge and that?s what I hit last time. Also When in Western Port Bay it is very tidal and have unfortunately found my self in shallow water doing some dredging LOL on a couple of Occasions, so for my purpose I think Alloy is the better option for now.

Yeah, we got a bridge like that too... When they were building it the concrete trucks would dump the excess into the river... So we got blocks of concrete to dodge too.... I like SS props because they are more tolerant of being dragged through the sand and mud, and because they are thinner and flex a lot less (particularly in high torque applications) They just 'feel' better. But each to his own....

cheers Andy

Look forward to seeing the water test results.... I did the whole fuel consumption/speed/revs thing and graphed it using excel.... Showed me a whole new aspect of where the best cruising speed is.

Cheers and keep us informed...

Chris.........

 

[4bait]

Re: Buick V6 conversion

Ok cant find a number oin the box because the seller has re painted it I guess but I have turned the drive shaft and it turns 1-3/4 turns to one turn of the prop. Haven't had a chance to compaire with the old leg as yet but will gat to it and check it soon.

here is an update of todays efforts have done it in 2 posts as the forum only accepts 6 pics at a time and I had 7 to put up




First was to fit the transom assembly, it lined up perfect to the old 470 hole and all that was needed was to drill 2 extra bolt holes in the top. I will however still need to pull the assembly apart as I will be replacing the drive shaft boot and gimble bearing and I also noticed the trim switch wires need replacing but it will be easier whilst mounted to the transom.

Next was to fit the exhaust Y pipe and this is where the drama's started to happen as the V6-V8 Mercruiser Pipe was too wide to fit in the boat and I couldn't get it into place because it hit the stringers and the engine bay walls (DOH)

I had two options here one was to cut some stringer out so it fitted and the other was to cut and change the angles of the Y Pipe and weld it back together again. I figured the second option would be better as the Holden exhaust would then also line up better and the pipe would also fit within the confines of the existing engine bay.

So I have chopped it up and stuck it together roughly to check it in the boat and will take it to work tomorrow to re-weld it.

Picture below is before chopping it up.

With the transom assy fitted and the Y pipe sort of in the right place, I decided I should drop the motor in and see how all the other things lined up incase i needed to make some more changes.

Everything from this point went in and lined up perfect so the engine mounts and bell housing ect are in the right positions Yeee Haaaa.
I Even dropped the alignment bar in and trued it up just to make sure.

the engine sits in the hole very nicely and there is heaps more room in the engine bay compaired to the old 4 cylinder 470 motor.

Oil filter mount misses the stringer nicely.

Alignment bar in place to check that it all sits in straight.

 

[4bait]

Re: Buick V6 conversion

The only other thing I had to do was cut a hole in the back here for the power steering ram to fit. This Peaved me off a bit because the batterys used to go in that spot. But I sort of didn'tlike the batterys there anyway so I think now I will put them in the old Kill tank under the floor or maybe put one in the engine bay now I have extra room there. MMM Need to think about that one a bit more.

So now the motor is back out again and I'm happy everything fits into place and I will refitt it all back in on the weekend for good once the exhaust has been welded up.


Cheers Andy

 

[4bait]

Re: Buick V6 conversion

did the cut and shut on the exhaust Y pipe today and have now made it smaller so it now fits into the confines of the boat. It was a bugger fitting it too because the person I got the transum assy of had snapped 2 studs off where it bolts upto and it had to be the 2 bottom ones that were a bugger to get too, so had to drill them out and re thread the holes. It would have been a much easier job had I noticed this first and drilled them in the mill before fitting to the boat. Oh well live and learn and check everything first LOL.

Here it is fitted and the motor will be going back in tomorrow

Cheers Andy

 

[walleye seeker]

Re: Buick V6 conversion

Holy cow you sure have put a boat load of work in that project and money as well. Nice work

 

[4bait]

Re: Buick V6 conversion

Holy cow you sure have put a boat load of work in that project and money as well. Nice work

Boat load of work yes...... Boat load of money No because I have done everything myself the only real expense so far was the purchase of the new/secondhand outdrive and the import and customs fee's etc.

Cheers Andy

 

[parrisw]

Re: Buick V6 conversion

Really great work, I look forward to seeing more!

 

[dieselram94]

Re: Buick V6 conversion

That is one cool project, it is so cool to see someone take on a project like this and also make some of the pieces as well. Nice work please keep the updates and pictures comming!!!!!!!!!!!!

 

[4bait]

Re: Buick V6 conversion

I didn't think to order a shift plate mechanism when I purchased the new out drive so first of all I modified the old 470 one but wasn't happy with the way it sat, and it was also bulky and had bits on it that the new system did not need, so I decided to fabricate my own so it sits in a nice out of the way spot but is still accessible. probably will paint these bits black later on.

Also got the throttle likages made up and working very well.

Still have a few issues to sort out, like where the heat exchanger will be living or do I make a custom one? Where to put the water separator filter, power steering reservoir brackets, electrical wiring etc etc but in general it's coming along ok.

Cheers Andy

 

[achris]

Re: Buick V6 conversion

Andy,

You need a shift interrupt switch on that shift plate. If you don't have one there, you'll destroy the dog clutch in the gearcase, and there's a good chance you'll break either of the shift cables.

Chris.....